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authorChris Wilson <chris@chris-wilson.co.uk>2010-08-07 11:01:35 +0100
committerEric Anholt <eric@anholt.net>2010-08-09 11:24:35 -0700
commit913d8d110078788c14812dce8bb62c37946821d2 (patch)
tree982a622078194b438bf75d0ee4c77cf1e4f0260e /drivers/gpu/drm/i915/intel_drv.h
parentdd785e35cb3c430c2290d351e67715864f7e5db5 (diff)
drm/i915: Ensure that while(INREG()) are bounded (v2)
Add a new macro, wait_for, to simplify the act of waiting on a register to change state. wait_for() takes three arguments, the condition to inspect on every loop, the maximum amount of time to wait and whether to yield the cpu for a length of time after each check. v2: Upgrade failure messages to DRM_ERROR on the suggestion of Eric Anholt. We do not expect to hit these conditions as they reflect programming errors, so if we do we want to be notified. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Eric Anholt <eric@anholt.net>
Diffstat (limited to 'drivers/gpu/drm/i915/intel_drv.h')
-rw-r--r--drivers/gpu/drm/i915/intel_drv.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index c552b06e5d2..2a3eaaf64b2 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -32,6 +32,20 @@
#include "drm_crtc.h"
#include "drm_crtc_helper.h"
+
+#define wait_for(COND, MS, W) ({ \
+ unsigned long timeout__ = jiffies + msecs_to_jiffies(MS); \
+ int ret__ = 0; \
+ while (! (COND)) { \
+ if (time_after(jiffies, timeout__)) { \
+ ret__ = -ETIMEDOUT; \
+ break; \
+ } \
+ if (W) msleep(W); \
+ } \
+ ret__; \
+})
+
/*
* Display related stuff
*/